Hi, Michael:
Some Orrefors pieces are marked only "Orrefors" or even "Of." In my limited experience, such pieces tend to be pieces produced in great numbers or are smaller, not particularly significant pieces. I'm surprised that a head would carry only an Orrefors, as that's likely to be a better piece, although I don't associate Orrefors with heads, more Kosta/Boda. I'd love to see a photograph, as I'm sure would others, perhaps with the mountains of Colorado in the background.
David